The present invention relates to a method for discharging cutting products from a metal-cutting machining process and to a metal-cutting machining process, in which a workpiece is machined by a tool, and in which cutting products are produced and are discharged.
In metal-cutting machining processes, such as, for example, turning, milling or drilling processes, a workpiece or product to be cut is machined by a tool in a cutting machine. In addition to cooling the workpiece and tool and lubricating the cut face, it is generally necessary to discharge cutting products, in particular chips and dust, which occur, so that they do not settle on the machine tool or in the machining space.
For this purpose, on the one hand, coolant lubrication can be carried out, in which large quantities of liquid are directed onto the cut face and thereby cool the workpiece and tool and, at the same time, cause lubrication. As a result of this, although good cooling and lubrication are achieved, in general, large quantities of liquid intermingled with the cutting products occur and subsequently, in turn, have to be discharged. For conditioning, the cutting products first have to be extracted from these liquid quantities which have occurred and then have to be cleared of liquid residues, so that they can subsequently, in turn, be used further, for example, melted down. This necessitates, correspondingly, a complicated and cost-intensive supply and discharge of the cooling lubricant and a reconditioning of the coolant and cutting products. Furthermore, liquid droplets intermingled with the cutting products may settle in the machining space, for example, on the machine tool, so that, in general, thorough cleaning of these is necessary after a lengthy period of operation. Moreover, in general, despite the machine tool being enclosed, the workstation becomes severely fouled with oil, so that the operating personnel may possibly also be contaminated.
Machining processes with minimal-quantity lubrication are also known, in which relatively small quantities of lubricant are supplied directly to the cut face, in particular via the tool. In these processes, there is no stream of cooling lubricant, so that the cutting products are discharged solely as a result of gravity and arrive at a discharge device, that is to say, a chip conveyor. Chips and dust particles, together with small quantities of lubricant, may therefore be deposited everywhere within the machine, so that, in the course of a day""s production, thick layers of dirt have to be cleaned off. This necessitates a high outlay in terms of corresponding production stoppages and sometimes manual cleaning operations. Furthermore, minimal-quantity lubrication cannot influence the generation of temperature, so that overheating problems may possibly arise.
DE 43 26 517 A1 discloses a process for the cutting machining of metallic workpieces with cooling, in which liquid CO2 emerges from a nozzle and expands, with the result that a mixture of gaseous cold carbon dioxide and dry ice is formed. This mixture is directed onto a machining point in the cutting machine of a metallic workpiece. The desired cooling of the machining point is thereby achieved.
One object of the present invention is to provide an improved method for discharging cutting products from a metal-cutting machining process, as compared with the prior art.
It is a particular object of the invention to provide a method for the discharge of cutting products and a metal-cutting machining process, by means of which high purity can be ensured at a relatively low outlay of equipment and material, and with low costs.
Further objects, features and advantages of the present invention will become apparent from the detailed description of preferred embodiments that follows, when considered together with the accompanying figure of drawing.
In accomplishing these and other objects, there has been provided according to one aspect of the present invention a method for discharging cutting products from a metal-cutting machining process in which a workpiece is subject to machining, comprising:
providing a gas stream;
introducing solid CO2 particles into the gas stream, to produce a gas stream with entrained CO2 particles; and
impinging the gas stream with entrained CO2 particles into a machining space, in which the machining process is carried out, and onto the workpiece in a region in the machining space in which the workpiece is subject to machining, such that at least a significant part of the cutting products produced by the machining is impacted upon by the gas stream in such a way that the cutting products are struck by the CO2 particles.
In accordance with another aspect of the invention, there has been provided a metal-cutting machining process, comprising:
machining a workpiece with a tool at a cut face, such that cutting products, including chips and/or dust, are produced;
discharging the cutting products according to a method for discharging cutting products as defined above, wherein the gas stream, together with entrained CO2 particles, impinges the workpiece and tool at least in the region of a cut face; and
further supplying a lubricant to the cut face via the tool.